Call-handling rules allow processing of incoming telephone calls based on external data. In some situations, telecommunication-related services and applications, such as Centrex, PBX, voice mail systems, and unified messaging systems, provide users with the ability to create call-handling rules to dictate how incoming phone calls should be handled. For example, a user can specify all incoming calls to her work phone be transferred to her home phone between 9 a.m. to 5 p.m., Monday to Friday. However, there are problems with conventional products that offer call-handling rules. Existing products support a limited set of conditions, which restricts the usefulness of the feature and revolve mainly around the concepts of call line identity, time-of-the-day, and what phone number the caller dialed. Further, existing solutions require users to provide necessary data directly into the product itself.